In the Party histories, of course, Big Brother figured as the leader and guardian of the Revolution since its very earliest days. His exploits had been gradually pushed backwards in time until already they extended into the fabulous world of the forties and the thirties.

George Orwell

1984. Part 1, Chapter 3. Does Big Brother actually exist? There may have been such a person, but Winston knows that the stories told about Big Brother change and become embellished over time. To the Party and the population, his symbolic meaning the important thing.